An inexperienced driver or an aged driver may have much difficulty in parking a vehicle, in particular, in a narrow space, and therefore a demand for a parking support system has increased. With the demand of a market and the recent increase in a vehicle in which a motor-driven power steering (MDPS) is equipped, the use of an ultrasonic based parking support system to relieve a driver's burden and improve driver convenience with a low cost has been increased.
As described above, according to the related art, in order to recognize a parking division space using an ultrasonic sensor, another vehicle or an obstacle beside the parking division space is required, or otherwise the accuracy of recognition of a valid parking division space may be reduced.
Further, a logic which is most fundamental in the parking support system according to the related art is a vehicle position estimator and a differential odometry scheme using rear wheel sensor data of a vehicle has been mainly used, in which the differential odometry may have reduced accuracy of recognizing the valid parking division space due to variables such as a vehicle specification and a road surface state.
An error in posture estimation of the odometry is called a systematic error, which corresponds to a deterministic error by the vehicle. An example of the cause of the systematic error may include a mismatch of two wheel diameters, a misalignment of the wheels, a kinematic modeling error, and the like.
Meanwhile, an apparatus for selecting a region of interest in an image provided from a means for detecting an image based parking division line based on an obstacle map, which is generated by a means for sensing an obstacle, to detect a parking division line, by using the means for sensing an obstacle and the means for detecting an image based parking division line is described in detail in European Patent No. EP2377728. As such, according to the related art, a method for determining a valid parking division based on the obstacle map when the detection of the image based parking division line fails, is described in detail and when the vehicle position estimation error is increased depending on the variables of the vehicle specification and the road surface state, the method may reduce the accuracy and recognition rate of a valid parking division.
When the vehicle position estimation error depending on the variables of the vehicle specification and the road surface state is increased, the error of the parking alignment may be increased during the parking. However, the related art does not yet provide a solution of the problems.